Charles Ebbets (attrib.), 1932. Eleven ironworkers lunching on a steel beam above 1930s Manhattan during the construction of 30 Rock.
From Wikipedia
Lunch atop a Skyscraper is a black-and-white photograph taken on September 20, 1932, of eleven ironworkers sitting on a steel beam of the RCA Building, 850 feet above the ground during the construction of Rockefeller Center in Manhattan, New York City. It was a staged photograph arranged as a publicity stunt, part of a campaign promoting the skyscraper.